Flexible media burnishing apparatus and method

ABSTRACT

An apparatus for burnishing media, according to one embodiment, includes a first block with a media bearing surface having a plurality of channels and lands. The channels and lands alternate in a direction of media travel. Each of the lands has at least one skiving edge along a width thereof. The width of each land extends orthogonally to the direction of media travel. The apparatus also includes a mechanism for inducing a wrap angle of the media relative to media bearing surfaces of at least some of the lands. Each induced wrap angle is greater than zero degrees. An apparatus for burnishing media according to another embodiment includes channels having widths that are less than a width of the media.

BACKGROUND

The present invention relates to data storage systems, and moreparticularly, this invention relates to an apparatus that may beparticularly useful for burnishing magnetic flexible media.

In magnetic storage systems, magnetic transducers read data from andwrite data onto magnetic recording media. Data is written on themagnetic recording media by moving a magnetic recording transducer to aposition over the media where the data is to be stored. The magneticrecording transducer then generates a magnetic field, which encodes thedata into the magnetic media. Data is read from the media by similarlypositioning the magnetic read transducer and then sensing the magneticfield of the magnetic media. Read and write operations may beindependently synchronized with the movement of the media to ensure thatthe data can be read from and written to the desired location on themedia.

An important and continuing goal in the data storage industry is that ofincreasing the density of data stored on a medium. For tape storagesystems, that goal has led to increasing the track and linear bitdensity on recording tape, and decreasing the thickness of the magnetictape medium. However, the development of small footprint, higherperformance tape drive systems has created various problems in thedesign of a tape head assembly for use in such systems.

In a tape drive system, the drive moves the magnetic tape over thesurface of the tape head at high speed. Usually the tape head isdesigned to minimize the spacing between the head and the tape. Thespacing between the magnetic head and the magnetic tape is crucial andso goals in these systems are to have the recording gaps of thetransducers, which are the source of the magnetic recording flux in nearcontact with the tape to effect writing sharp transitions, and to havethe read elements in near contact with the tape to provide effectivecoupling of the magnetic field from the tape to the read elements.

SUMMARY

An apparatus for burnishing media, according to one embodiment, includesa first block with a media bearing surface having a plurality ofchannels and lands. The channels and lands alternate in a direction ofmedia travel. Each of the lands has at least one skiving edge along awidth thereof. The width of each land extends orthogonally to thedirection of media travel. The apparatus also includes a mechanism forinducing a wrap angle of the media relative to media bearing surfaces ofat least some of the lands. Each induced wrap angle is greater than zerodegrees.

An apparatus for burnishing media, according to another embodiment,includes a first block with a media bearing surface having a pluralityof channels and lands. The channels and lands alternate in a directionof media travel. Each of the lands has at least one skiving edge along awidth thereof. The width of each land extends orthogonally to thedirection of media travel. The apparatus also includes a mechanism forinducing a wrap angle of the media relative to media bearing surfaces ofat least some of the lands. Each induced wrap angle is greater than zerodegrees. In addition, the apparatus includes a mechanism for removingaccumulated debris from the channels.

According to yet another embodiment, a method for burnishing mediaincludes setting a wrap angle of a media relative to a media bearingsurface of an apparatus. The apparatus includes a first block with amedia bearing surface having a plurality of channels and lands, wherethe channels and lands alternate in a direction of media travel. Each ofthe lands of the apparatus has at least one skiving edge along a widththereof, the width of each land extending orthogonally to the directionof media travel. In addition, the method includes running the media overthe first block in the direction of media travel. Accumulated debris maybe removed from at least some of the channels.

Any of these embodiments may be implemented in a system such as a tapedrive system, which may include a magnetic head, a drive mechanism forpassing a magnetic medium (e.g., recording tape) over the magnetic head,and a controller electrically coupled to the magnetic head.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of a simplified tape drive systemaccording to one embodiment.

FIG. 1B is a schematic diagram of a tape cartridge according to oneembodiment.

FIG. 2 illustrates a side view of a flat-lapped, bi-directional,two-module magnetic tape head according to one embodiment.

FIG. 2A is a tape bearing surface view taken from Line 2A of FIG. 2.

FIG. 2B is a detailed view taken from Circle 2B of FIG. 2A.

FIG. 2C is a detailed view of a partial tape bearing surface of a pairof modules.

FIG. 3 is a partial tape bearing surface view of a magnetic head havinga write-read-write configuration.

FIG. 4 is a partial tape bearing surface view of a magnetic head havinga read-write-read configuration.

FIG. 5 is a side view of a magnetic tape head with three modulesaccording to one embodiment where the modules all generally lie alongabout parallel planes.

FIG. 6 is a side view of a magnetic tape head with three modules in atangent (angled) configuration.

FIG. 7 is a side view of a magnetic tape head with three modules in anoverwrap configuration.

FIG. 8A is a top down view of a block for burnishing tape mediaaccording to one embodiment.

FIG. 8B is a cross sectional side view taken along Line 8B-8B of FIG.8A.

FIG. 8C is a perspective view of the block of FIG. 8A.

FIG. 8D is a top down view of a block for burnishing tape mediaaccording to one embodiment.

FIG. 9 is a cross-sectional side view of a block for burnishing tapemedia according to one embodiment.

FIG. 10 is a side view of a set of blocks for burnishing tape mediaaccording to one embodiment.

FIG. 11 is a side view of a set of blocks for burnishing tape mediaaccording to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

The following description discloses several preferred embodiments ofmagnetic storage systems, as well as operation and/or component partsthereof.

In one general embodiment, an apparatus for burnishing media includes afirst block with a media bearing surface having a plurality of channelsand lands. The channels and lands alternate in a direction of mediatravel. Each of the lands has at least one skiving edge along a widththereof. The width of each land extends orthogonally to the direction ofmedia travel. The apparatus also includes a mechanism for inducing awrap angle of the media relative to media bearing surfaces of at leastsome of the lands. Each induced wrap angle is greater than zero degrees.

In another general embodiment, an apparatus for burnishing mediaincludes a first block with a media bearing surface having a pluralityof channels and lands. The channels and lands alternate in a directionof media travel. Each of the lands has at least one skiving edge along awidth thereof, the width of each land extending orthogonally to thedirection of media travel. A width of at least some of the channels isless than a width of the media.

FIG. 1A illustrates a simplified tape drive 100 of a tape-based datastorage system, which may be employed in the context of the presentinvention. While one specific implementation of a tape drive is shown inFIG. 1A, it should be noted that the embodiments described herein may beimplemented in the context of any type of tape drive system.

As shown, a tape supply cartridge 120 and a take-up reel 121 areprovided to support a tape 122. One or more of the reels may form partof a removable cartridge and are not necessarily part of the system 100.The tape drive, such as that illustrated in FIG. 1A, may further includedrive motor(s) to drive the tape supply cartridge 120 and the take-upreel 121 to move the tape 122 over a tape head 126 of any type. Suchhead may include an array of readers, writers, or both.

Guides 125 guide the tape 122 across the tape head 126. Such tape head126 is in turn coupled to a controller 128 via a cable 130. Thecontroller 128, may be or include a processor and/or any logic forcontrolling any subsystem of the drive 100. For example, the controller128 typically controls head functions such as servo following, datawriting, data reading, etc. The controller 128 may include at least oneservo channel and at least one data channel, each of which include dataflow processing logic configured to process and/or store information tobe written to and/or read from the tape 122. The controller 128 mayoperate under logic known in the art, as well as any logic disclosedherein, and thus may be considered as a processor for any of thedescriptions of tape drives included herein, in various embodiments. Thecontroller 128 may be coupled to a memory 136 of any known type, whichmay store instructions executable by the controller 128. Moreover, thecontroller 128 may be configured and/or programmable to perform orcontrol some or all of the methodology presented herein. Thus, thecontroller 128 may be considered to be configured to perform variousoperations by way of logic programmed into one or more chips, modules,and/or blocks; software, firmware, and/or other instructions beingavailable to one or more processors; etc., and combinations thereof.

The cable 130 may include read/write circuits to transmit data to thehead 126 to be recorded on the tape 122 and to receive data read by thehead 126 from the tape 122. An actuator 132 controls position of thehead 126 relative to the tape 122.

An interface 134 may also be provided for communication between the tapedrive 100 and a host (internal or external) to send and receive the dataand for controlling the operation of the tape drive 100 andcommunicating the status of the tape drive 100 to the host, all as willbe understood by those of skill in the art.

FIG. 1B illustrates an exemplary tape cartridge 150 according to oneembodiment. Such tape cartridge 150 may be used with a system such asthat shown in FIG. 1A. As shown, the tape cartridge 150 includes ahousing 152, a tape 122 in the housing 152, and a nonvolatile memory 156coupled to the housing 152. In some approaches, the nonvolatile memory156 may be embedded inside the housing 152, as shown in FIG. 1B. In moreapproaches, the nonvolatile memory 156 may be attached to the inside oroutside of the housing 152 without modification of the housing 152. Forexample, the nonvolatile memory may be embedded in a self-adhesive label154. In one preferred embodiment, the nonvolatile memory 156 may be aFlash memory device, ROM device, etc., embedded into or coupled to theinside or outside of the tape cartridge 150. The nonvolatile memory isaccessible by the tape drive and the tape operating software (the driversoftware), and/or another device.

By way of example, FIG. 2 illustrates a side view of a flat-lapped,bi-directional, two-module magnetic tape head 200 which may beimplemented in the context of the present invention. As shown, the headincludes a pair of bases 202, each equipped with a module 204, and fixedat a small angle α with respect to each other. The bases may be“U-beams” that are adhesively coupled together. Each module 204 includesa substrate 204A and a closure 204B with a thin film portion, commonlyreferred to as a “gap” in which the readers and/or writers 206 areformed. In use, a tape 208 is moved over the modules 204 along a media(tape) bearing surface 209 in the manner shown for reading and writingdata on the tape 208 using the readers and writers. The wrap angle θ ofthe tape 208 at edges going onto and exiting the flat media supportsurfaces 209 are usually between about 0.1 degree and about 3 degrees.

The substrates 204A are typically constructed of a wear resistantmaterial, such as a ceramic. The closures 204B may be made of the sameor similar ceramic as the substrates 204A.

The readers and writers may be arranged in a piggyback or mergedconfiguration. An illustrative piggybacked configuration comprises a(magnetically inductive) writer transducer on top of (or below) a(magnetically shielded) reader transducer (e.g., a magnetoresistivereader, etc.), wherein the poles of the writer and the shields of thereader are generally separated. An illustrative merged configurationcomprises one reader shield in the same physical layer as one writerpole (hence, “merged”). The readers and writers may also be arranged inan interleaved configuration. Alternatively, each array of channels maybe readers or writers only. Any of these arrays may contain one or moreservo track readers for reading servo data on the medium.

FIG. 2A illustrates the tape bearing surface 209 of one of the modules204 taken from Line 2A of FIG. 2. A representative tape 208 is shown indashed lines. The module 204 is preferably long enough to be able tosupport the tape as the head steps between data bands.

In this example, the tape 208 includes 4 to 32 data bands, e.g., with 16data bands and 17 servo tracks 210, as shown in FIG. 2A on a one-halfinch wide tape 208. The data bands are defined between servo tracks 210.Each data band may include a number of data tracks, for example 1024data tracks (not shown). During read/write operations, the readersand/or writers 206 are positioned to specific track positions within oneof the data bands. Outer readers, sometimes called servo readers, readthe servo tracks 210. The servo signals are in turn used to keep thereaders and/or writers 206 aligned with a particular set of tracksduring the read/write operations.

FIG. 2B depicts a plurality of readers and/or writers 206 formed in agap 218 on the module 204 in Circle 2B of FIG. 2A. As shown, the arrayof readers and writers 206 includes, for example, 16 writers 214, 16readers 216 and two servo readers 212, though the number of elements mayvary. Illustrative embodiments include 8, 16, 32, 40, and 64 activereaders and/or writers 206 per array, and alternatively interleaveddesigns having odd numbers of reader or writers such as 17, 25, 33, etc.An illustrative embodiment includes 32 readers per array and/or 32writers per array, where the actual number of transducer elements couldbe greater, e.g., 33, 34, etc. This allows the tape to travel moreslowly, thereby reducing speed-induced tracking and mechanicaldifficulties and/or execute fewer “wraps” to fill or read the tape.While the readers and writers may be arranged in a piggybackconfiguration as shown in FIG. 2B, the readers 216 and writers 214 mayalso be arranged in an interleaved configuration. Alternatively, eacharray of readers and/or writers 206 may be readers or writers only, andthe arrays may contain one or more servo readers 212. As noted byconsidering FIGS. 2 and 2A-B together, each module 204 may include acomplementary set of readers and/or writers 206 for such things asbi-directional reading and writing, read-while-write capability,backward compatibility, etc.

FIG. 2C shows a partial tape bearing surface view of complementarymodules of a magnetic tape head 200 according to one embodiment. In thisembodiment, each module has a plurality of read/write (R/W) pairs in apiggyback configuration formed on a common substrate 204A and anoptional electrically insulative layer 236. The writers, exemplified bythe write transducer 214 and the readers, exemplified by the readtransducer 216, are aligned parallel to an intended direction of travelof a tape medium thereacross to form an R/W pair, exemplified by the R/Wpair 222. Note that the intended direction of tape travel is sometimesreferred to herein as the direction of tape travel, and such terms maybe used interchangeably. Such direction of tape travel may be inferredfrom the design of the system, e.g., by examining the guides; observingthe actual direction of tape travel relative to the reference point;etc. Moreover, in a system operable for bi-direction reading and/orwriting, the direction of tape travel in both directions is typicallyparallel and thus both directions may be considered equivalent to eachother.

Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc. TheR/W pairs 222 as shown are linearly aligned in a direction generallyperpendicular to a direction of tape travel thereacross. However, thepairs may also be aligned diagonally, etc. Servo readers 212 arepositioned on the outside of the array of R/W pairs, the function ofwhich is well known.

Generally, the magnetic tape medium moves in either a forward or reversedirection as indicated by arrow 220. The magnetic tape medium and headassembly 200 operate in a transducing relationship in the mannerwell-known in the art. The piggybacked MR head assembly 200 includes twothin-film modules 224 and 226 of generally identical construction.

Modules 224 and 226 are joined together with a space present betweenclosures 204B thereof (partially shown) to form a single physical unitto provide read-while-write capability by activating the writer of theleading module and reader of the trailing module aligned with the writerof the leading module parallel to the direction of tape travel relativethereto. When a module 224, 226 of a piggyback head 200 is constructed,layers are formed in the gap 218 created above an electricallyconductive substrate 204A (partially shown), e.g., of AlTiC, ingenerally the following order for the R/W pairs 222: an insulating layer236, a first shield 232 typically of an iron alloy such as NiFe (−),cobalt zirconium tantalum (CZT) or Al—Fe—Si (Sendust), a sensor 234 forsensing a data track on a magnetic medium, a second shield 238 typicallyof a nickel-iron alloy (e.g., ˜80/20 at % NiFe, also known aspermalloy), first and second writer pole tips 228, 230, and a coil (notshown). The sensor may be of any known type, including those based onMR, GMR, AMR, tunneling magnetoresistance (TMR), etc.

The first and second writer poles 228, 230 may be fabricated from highmagnetic moment materials such as ˜45/55 NiFe. Note that these materialsare provided by way of example only, and other materials may be used.Additional layers such as insulation between the shields and/or poletips and an insulation layer surrounding the sensor may be present.Illustrative materials for the insulation include alumina and otheroxides, insulative polymers, etc.

The configuration of the tape head 126 according to one embodimentincludes multiple modules, preferably three or more. In awrite-read-write (W-R-W) head, outer modules for writing flank one ormore inner modules for reading. Referring to FIG. 3, depicting a W-R-Wconfiguration, the outer modules 252, 256 each include one or morearrays of writers 260. The inner module 254 of FIG. 3 includes one ormore arrays of readers 258 in a similar configuration. Variations of amulti-module head include a R-W-R head (FIG. 4), a R-R-W head, a W-W-Rhead, etc. In yet other variations, one or more of the modules may haveread/write pairs of transducers. Moreover, more than three modules maybe present. In further approaches, two outer modules may flank two ormore inner modules, e.g., in a W-R-R-W, a R-W-W-R arrangement, etc. Forsimplicity, a W-R-W head is used primarily herein to exemplifyembodiments of the present invention. One skilled in the art apprisedwith the teachings herein will appreciate how permutations of thepresent invention would apply to configurations other than a W-R-Wconfiguration.

FIG. 5 illustrates a magnetic head 126 according to one embodiment ofthe present invention that includes first, second and third modules 302,304, 306 each having a tape bearing surface 308, 310, 312 respectively,which may be flat, contoured, etc. Note that while the term “tapebearing surface” appears to imply that the surface facing the tape 315is in physical contact with the tape bearing surface, this is notnecessarily the case. Rather, only a portion of the tape may be incontact with the tape bearing surface, constantly or intermittently,with other portions of the tape riding (or “flying”) above the tapebearing surface on a layer of air, sometimes referred to as an “airbearing”. The first module 302 will be referred to as the “leading”module as it is the first module encountered by the tape in a threemodule design for tape moving in the indicated direction. The thirdmodule 306 will be referred to as the “trailing” module. The trailingmodule follows the middle module and is the last module seen by the tapein a three module design. The leading and trailing modules 302, 306 arereferred to collectively as outer modules. Also note that the outermodules 302, 306 will alternate as leading modules, depending on thedirection of travel of the tape 315.

In one embodiment, the tape bearing surfaces 308, 310, 312 of the first,second and third modules 302, 304, 306 lie on about parallel planes(which is meant to include parallel and nearly parallel planes, e.g.,between parallel and tangential as in FIG. 6), and the tape bearingsurface 310 of the second module 304 is above the tape bearing surfaces308, 312 of the first and third modules 302, 306. As described below,this has the effect of creating the desired wrap angle α₂ of the taperelative to the tape bearing surface 310 of the second module 304.

Where the tape bearing surfaces 308, 310, 312 lie along parallel ornearly parallel yet offset planes, intuitively, the tape should peel offof the tape bearing surface 308 of the leading module 302. However, thevacuum created by the skiving edge 318 of the leading module 302 hasbeen found by experimentation to be sufficient to keep the tape adheredto the tape bearing surface 308 of the leading module 302. The trailingedge 320 of the leading module 302 (the end from which the tape leavesthe leading module 302) is the approximate reference point which definesthe wrap angle α₂ over the tape bearing surface 310 of the second module304. The tape stays in close proximity to the tape bearing surface untilclose to the trailing edge 320 of the leading module 302. Accordingly,read and/or write elements 322 may be located near the trailing edges ofthe outer modules 302, 306. These embodiments are particularly adaptedfor write-read-write applications.

A benefit of this and other embodiments described herein is that,because the outer modules 302, 306 are fixed at a determined offset fromthe second module 304, the inner wrap angle α₂ is fixed when the modules302, 304, 306 are coupled together or are otherwise fixed into a head.The inner wrap angle α₂ is approximately tan⁻¹ (δ/W) where δ is theheight difference between the planes of the tape bearing surfaces 308,310 and W is the width between the opposing ends of the tape bearingsurfaces 308, 310. An illustrative inner wrap angle α₂ is in a range ofabout 0.3° to about 1.1°, though can be any angle required by thedesign.

Beneficially, the inner wrap angle α₂ on the side of the module 304receiving the tape (leading edge) will be larger than the inner wrapangle α₃ on the trailing edge, as the tape 315 rides above the trailingmodule 306. This difference is generally beneficial as a smaller α₃tends to oppose what has heretofore been a steeper exiting effectivewrap angle.

Note that the tape bearing surfaces 308, 312 of the outer modules 302,306 are positioned to achieve a negative wrap angle at the trailing edge320 of the leading module 302. This is generally beneficial in helpingto reduce friction due to contact with the trailing edge 320, providedthat proper consideration is given to the location of the crowbar regionthat forms in the tape where it peels off the head. This negative wrapangle also reduces flutter and scrubbing damage to the elements on theleading module 302. Further, at the trailing module 306, the tape 315flies over the tape bearing surface 312 so there is virtually no wear onthe elements when tape is moving in this direction. Particularly, thetape 315 entrains air and so will not significantly ride on the tapebearing surface 312 of the third module 306 (some contact may occur).This is permissible, because the leading module 302 is writing while thetrailing module 306 is idle.

Writing and reading functions are performed by different modules at anygiven time. In one embodiment, the second module 304 includes aplurality of data and optional servo readers 331 and no writers. Thefirst and third modules 302, 306 include a plurality of writers 322 andno data readers, with the exception that the outer modules 302, 306 mayinclude optional servo readers. The servo readers may be used toposition the head during reading and/or writing operations. The servoreader(s) on each module are typically located towards the end of thearray of readers or writers.

By having only readers or side by side writers and servo readers in thegap between the substrate and closure, the gap length can besubstantially reduced. Typical heads have piggybacked readers andwriters, where the writer is formed above each reader. A typical gap is20-35 microns. However, irregularities on the tape may tend to droopinto the gap and create gap erosion. Thus, the smaller the gap is thebetter. The smaller gap enabled herein exhibits fewer wear relatedproblems.

In some embodiments, the second module 304 has a closure, while thefirst and third modules 302, 306 do not have a closure. Where there isno closure, preferably a hard coating is added to the module. Onepreferred coating is diamond-like carbon (DLC).

In the embodiment shown in FIG. 5, the first, second, and third modules302, 304, 306 each have a closure 332, 334, 336, which extends the tapebearing surface of the associated module, thereby effectivelypositioning the read/write elements away from the edge of the tapebearing surface. The closure 332 on the second module 304 can be aceramic closure of a type typically found on tape heads. The closures334, 336 of the first and third modules 302, 306, however, may beshorter than the closure 332 of the second module 304 as measuredparallel to a direction of tape travel over the respective module. Thisenables positioning the modules closer together. One way to produceshorter closures 334, 336 is to lap the standard ceramic closures of thesecond module 304 an additional amount. Another way is to plate ordeposit thin film closures above the elements during thin filmprocessing. For example, a thin film closure of a hard material such asSendust or nickel-iron alloy (e.g., 45/55) can be formed on the module.

With reduced-thickness ceramic or thin film closures 334, 336 or noclosures on the outer modules 302, 306, the write-to-read gap spacingcan be reduced to less than about 1 mm, e.g., about 0.75 mm, or 50% lessthan commonly-used LTO tape head spacing. The open space between themodules 302, 304, 306 can still be set to approximately 0.5 to 0.6 mm,which in some embodiments is ideal for stabilizing tape motion over thesecond module 304.

Depending on tape tension and stiffness, it may be desirable to anglethe tape bearing surfaces of the outer modules relative to the tapebearing surface of the second module. FIG. 6 illustrates an embodimentwhere the modules 302, 304, 306 are in a tangent or nearly tangent(angled) configuration. Particularly, the tape bearing surfaces of theouter modules 302, 306 are about parallel to the tape at the desiredwrap angle α₂ of the second module 304. In other words, the planes ofthe tape bearing surfaces 308, 312 of the outer modules 302, 306 areoriented at about the desired wrap angle α₂ of the tape 315 relative tothe second module 304. The tape will also pop off of the trailing module306 in this embodiment, thereby reducing wear on the elements in thetrailing module 306. These embodiments are particularly useful forwrite-read-write applications. Additional aspects of these embodimentsare similar to those given above.

Typically, the tape wrap angles may be set about midway between theembodiments shown in FIGS. 5 and 6.

FIG. 7 illustrates an embodiment where the modules 302, 304, 306 are inan overwrap configuration. Particularly, the tape bearing surfaces 308,312 of the outer modules 302, 306 are angled slightly more than the tape315 when set at the desired wrap angle α₂ relative to the second module304. In this embodiment, the tape does not pop off of the trailingmodule, allowing it to be used for writing or reading. Accordingly, theleading and middle modules can both perform reading and/or writingfunctions while the trailing module can read any just-written data.Thus, these embodiments are preferred for write-read-write,read-write-read, and write-write-read applications. In the latterembodiments, closures should be wider than the tape canopies forensuring read capability. The wider closures may require a widergap-to-gap separation. Therefore, a preferred embodiment has awrite-read-write configuration, which may use shortened closures thatthus allow closer gap-to-gap separation.

Additional aspects of the embodiments shown in FIGS. 6 and 7 are similarto those given above.

A 32 channel version of a multi-module head 126 may use cables 350having leads on the same or smaller pitch as current 16 channelpiggyback LTO modules, or alternatively the connections on the modulemay be organ-keyboarded for a 50% reduction in cable span. Over-under,writing pair unshielded cables may be used for the writers, which mayhave integrated servo readers.

The outer wrap angles α₁ may be set in the drive, such as by guides ofany type known in the art, such as adjustable rollers, slides, etc. oralternatively by outriggers, which are integral to the head. Forexample, rollers having an offset axis may be used to set the wrapangles. The offset axis creates an orbital arc of rotation, allowingprecise alignment of the wrap angle α₁.

To assemble any of the embodiments described above, conventional u-beamassembly can be used. Accordingly, the mass of the resultant head may bemaintained or even reduced relative to heads of previous generations. Inother approaches, the modules may be constructed as a unitary body.Those skilled in the art, armed with the present teachings, willappreciate that other known methods of manufacturing such heads may beadapted for use in constructing such heads. Moreover, unless otherwisespecified, processes and materials of types known in the art may beadapted for use in various embodiments in conformance with the teachingsherein, as would become apparent to one skilled in the art upon readingthe present disclosure.

Servo pattern and data read sensors may experience shorting failuresduring normal data writing and/or reading operations. Particularly, suchshorting may be caused by protruding defects (herein “surface defects”)in the magnetic tape recording media (also generically referred to as“tape”), such as agglomerations of abrasive particles or other defects,e.g., hard particulates, that protrude from the tape surface. Suchsurface defects may smear and/or plow conductive material from the thinfilms of the reader across the sensor, thereby creating an electricalshort.

While this issue is relevant to current-perpendicular-to-plane (CPP)readers in general, this problem is particularly problematic with CPPTMR sensors. Because the deposition thickness of the tunnel barrier theTMR sensor is very thin, e.g., less than about 12 angstroms in someapproaches. TMR sensors may be particularly susceptible to suchshorting.

Interactions between tape media surface defects and a sensor surface mayalso lead to friction-related functionality issues. For example, when asurface defect passes over a sensor, friction may lead to plasticdeformation of one or more delicate thin films of the sensor. Plasticdeformation of the delicate thin films may alter the stress distributioninside the sensor, which in turn may be presented as noise due tomagnetic instability, e.g., switching magnetic domains.

Narrower write heads may also be subject to degradation via spacing lossresulting from gouges caused by tape surface defects. Such problematictape surface defects may protrude from the surface of the tape, and mayinclude one or more agglomerations of abrasive particles. The surfacedefects may also include dense agglomerations of binder materials, wearparticles, isolated particle defects, etc.

Such surface defects may result from, e.g., the milling of particlesused in the tape, e.g., where a larger particle is inadvertently addedto the tape media during manufacture.

Despite filtering systems and quality control used by tape mediamanufacturers, including tape burnishing via lapping tape, some tapesstill contain defects that are capable of damaging magnetic tape heads.As the defective media runs over the TMR structure of the sensor, aconductive smear may develop leading to a short of the head. As aresult, the sensor shows a resistance reduction with a loss of output.Thus, it would be desirable to pre-condition the media by blunting andsmoothing the defects before running the media over the tape head.

Conventional methods of cleaning or running the newly manufacturedmagnetic recording media over a blade are not sufficient topre-condition and remove particulate defects from the media for runningover a TMR sensor, because particulate defects are often persistent andresistant to burnishing during operating a drive. For example, aparticulate defect that remains after the manufacturing process anddamages a track on a head may also have the ability to damage the sametrack on a head in another drive. It would be desirable for theburnishing method of pre-conditioning defective tapes to involve anapparatus that is harder than the particulates in the media in order toprevent the particulate debris from damaging the TMR sensor.

Various embodiments described herein involve an apparatus having a hardmaterial that wraps the tape under tension on sharp edges at differentangles in a repetitive manner to blunt the defects and ultimately smooththe tape surface.

FIGS. 8A-8C depict an apparatus 800 for burnishing tape media, inaccordance with one embodiment. As an option, the apparatus 800 may beimplemented in conjunction with features from any other embodimentlisted herein, such as those described with reference to the other FIGS.Of course, however, such an apparatus 800 and others presented hereinmay be used in various applications and/or in permutations which may ormay not be specifically described in the illustrative embodiments listedherein. Further, the apparatus 800 presented herein may be used in anydesired environment.

According to one embodiment as shown in FIGS. 8A-8B, the apparatus 800for burnishing media includes a first block 820 with a media bearingsurface 805 having a plurality of channels 806 and lands 804, where thechannels 806 and lands 804 may alternate in a direction of media travel816. Looking to FIG. 8B, each of the lands 804 may have at least oneskiving edge 808 along a width w in which the width w of each land 804extending orthogonally to the direction of media travel 816.

Preferably, at least some of the channels 806 may be physicallyconfigured to reduce pressure 810 in the channel to below ambientpressure, creating a subambient condition therein, and thereby causingthe media 814 to wrap an adjacent skiving edge 808 at a wrap angle φ asthe media 814 travels in the direction of media travel 816 (as shown inFIG. 8B).

In some embodiments, widths w_(e) of one or more of the channels may beless than a width w_(m) of the media fir which the apparatus isdesigned. See FIG. 8A and the perspective view of FIG. 8C).

Looking to FIGS. 8A-8C, in some embodiments, because ends of thechannels are closed and the widths w_(e) of the channels are less thanthe width of the media, a sub-ambient pressure 810 is created under themedia 814 when the media moves over the channels and entrains air out ofthe channel. The resultant subambient condition induces the media 814 todeflect into the channels 806 and wrap the edges 808 at a wrap angle φ.

In preferred approaches, the induced wrap angle φ may be greater thanzero degrees as measured between a plane 812 of the tape bearing surfaceand a straight line 813 tangent to the tape adjacent the edge 808 andintersecting the edge 808. See the detailed excerpt in FIG. 8B.

According to one embodiment, the first block 820 may include at leastone hard material, for example, silicon carbide, silicon nitride, boronnitride, sapphire, and/or diamond. In another embodiment, the firstblock 820 may include at least one composite material, for example,composite materials used in tool fabrication, such as silicon, zirconiumnitride, AlTiC, silicon carbide, sapphire, etc.

A guide mechanism such as guides in FIG. 1A may be configured to set awrap angle of a tape approaching the outermost skiving edges of theblock. The guide mechanism may include, e.g., tape guides such as guides125 of FIG. 1A, pitch rollers, a tension arm, etc.

The outermost wrap angle may be set, e.g., by the guide mechanism, toany angle that promotes the burnishing of surface defects off the tapemedia surface. According to one embodiment, the wrap angle may be atleast one degree. According to preferred embodiments, the wrap angle maybe in a range of about two to about three degrees.

Similarly, the induced wrap angle φ adjacent each land is preferablygreater than 0 degrees. In general, a wrap angle higher than one degreeis greater than would be used for conventional read/write operationsbecause the high wrap angle results in higher friction, which isbeneficial for burnishing but is not only unnecessary for read/writeoperations, but excessive friction can lead to deleterious velocityvariations of the tape during read/write operations.

The optimal wrap angle to give the best burnishing effect may be limitedby the degree of running friction of the tape media caused by the wrapangle. According to one embodiment, each induced wrap angle φ is in arange of about 0.1 to about 3 degrees, but may be higher or lower.

Looking to FIGS. 8B-8C, the media bearing surface 805 of each of thelands 804 may be planar, ideally with sharp, non-cusped edges 808. Theheight h of the lands 804 above a base of the channels 806 may be anyvalue, and may be selected to provide a vacuum that provides the desiredinduced wrap angle φ. The height h of the lands 804 above a base of thechannels 806 may be determined using datum structures or any otherconventional technique. Exemplary values of the height h may include 0.5microns to 10 microns, but could be higher or lower in variousembodiments.

The length of each land as measured parallel to the direction of mediatravel 816 is preferably no longer than needed for the particularapplication, e.g., to reduce friction. In some embodiments, the lengthsof the lands are preferably at least 100 microns in order to allow thewrap angles to form, but could be longer or shorter.

The length of each channel as measured parallel to the direction ofmedia travel 816 may be any value, but is preferably at least as long asthe length of the lands.

The channels may be formed using any suitable process. Forclosed-channel embodiments such as shown in FIG. 8A, etching may bepreferred. In other approaches, the channels may be formed by machininge.g., by sawing or grinding.

In some embodiments, the media bearing surface 805 of the lands 804 maynot be smooth, but rather have a roughened or bumpy texture. Whileconventional techniques for texturing a surface may be used, anexemplary method of roughening the lands may include employing anair-bearing spindle saw and/or an abrasive wheel. In other approaches,the texture may be formed on the media bearing surface, e.g., by moldingduring ceramic formation. In some approaches, about 50 nm of RA ofsurface roughness on the lands, or higher, may reduce friction of thetape media running over the lands.

According to one embodiment of a method for using the apparatus 800, themethod may involve running the media 814 over the first block 820 in thedirection of media travel 816 and/or the opposite direction one or moretimes.

In some approaches, the apparatus 800 may include a mechanism 850 forremoving accumulated debris from the channels 806. See FIG. 8C. In oneapproach, a brush may sweep through the channels 806 at periodicintervals. In another approach, the mechanism may use compressed air.Further approaches may use a fabric, swab or the like to wipe awaydebris. In further approaches, a rotating, vibrating or otherwise movingmechanism may be used. The mechanism 850 may be automated, operate ondemand, etc.

One embodiment of apparatus 800 may include a drive mechanism such as amotor or other known mechanism that is configured to cause the tape tomove over the first block and a controller electrically coupled to thedrive mechanism. For example, the motor or other known mechanism maydrive a tape supply cartridge, e.g., tape supply cartridge 120 of FIG.1A, and a take-up reel, e.g., take-up reel 121 also of FIG. 1A, of adrive in which the block is implemented in, to move the tape media overthe block and/or other components of the drive.

FIG. 8D depicts a variant of FIG. 8A, where the channels 806 are widerthan the width W_(m) of the media 814.

In one embodiment, the apparatus may include a mechanism for inducing awrap angle, of greater than zero degrees, of the media relative to mediabearing surfaces of at least some of the lands. As will be describedbelow with reference to FIGS. 9-11, such mechanism may include suchfeatures as a vacuum source, a second block, applied air pressure, andcombinations thereof, in some approaches.

FIG. 9 depicts an apparatus 900 for burnishing tape media, in accordancewith one embodiment. As an option, the apparatus 900 may be implementedin conjunction with features from any other embodiment listed herein,such as those described with reference to the other FIGS. Of course,however, such an apparatus 900 and others presented herein may be usedin various applications and/or in permutations which may or may not bespecifically described in the illustrative embodiments listed herein.Further, the apparatus 900 presented herein may be used in any desiredenvironment.

According to one embodiment as shown in FIG. 9, an apparatus 900includes channels 906 of the first block 920 having an opening 922, e.g.cylindrical holes, slots, etc, that may connect to a vacuum source 926.The vacuum source 926 may create a subambient condition in one or moreof the channels that urges the media toward the media bearing surfacesof the lands in the direction 924 orthogonal to the plane 812 of themedia bearing surface. Each of the lands 904 may have at least oneskiving edge 908 along a width of each land 904 extending orthogonallyto the direction of media travel 816.

According to one embodiment, the subambient condition created by thevacuum source may induce wrap angles of the media relative to the tapebearing surface of each land. Moreover, the induced wrap angles may becommonly and/or individually adjusted, e.g., to a low or high wrapangle, by controlling the amount of vacuum applied by the vacuum source926, potentially on a channel by channel basis.

According to another embodiment, an apparatus for burnishing tape mediamay include two blocks made of different materials or the samematerials. The lands of the upper block may push the tape media into thechannels of the lower block by pushing downward against the back of thetape media.

FIG. 10 depicts an apparatus 1000 for burnishing tape media, inaccordance with one embodiment. As an option, the apparatus 1000 may beimplemented in conjunction with features from any other embodimentlisted herein, such as those described with reference to the other FIGS.Of course, however, such an apparatus 1000 and others presented hereinmay be used in various applications and/or in permutations which may ormay not be specifically described in the illustrative embodiments listedherein. Further, the apparatus 1000 presented herein may be used in anydesired environment.

According to one embodiment as shown in FIG. 10, an apparatus 1000 forburnishing media includes a first block 1020 with a media bearingsurface extending along a plane 812. The first block 1020 has aplurality of channels 1006 and lands 1004. The channels 1006 and lands1004 may alternate in a direction of media travel 816. Each of the lands1004 may have at least one skiving edge 1008 along a width thereof, thewidth of each land 1004 extending orthogonally (into the sheet of FIG.10) to the direction of media travel 816. The apparatus 1000 has asecond block 1030 positioned above the media bearing surface of thefirst block 1020. The second block 1030 has lands 1034 positionedrelative to the first block 1020 to push the media into the channels1006 of the first block 1020 to cause the media to wrap the skivingedges 1008 at induced wrap angles as the media travels in the directionof media travel 816. In some approaches, the induced wrap angles may beset by adjusting the extent of protrusion of the lands 1034 of thesecond block 1030 into the channels 1006 of the first block 1020, e.g.,by using positioners with nanometer precision so that, conversely, thesecond block 1030 may have channels 1036 that fit the lands 1004 of thefirst block 1020. Preferably, each induced wrap angle may be greaterthan zero degrees, and ideally greater than 1 degree.

In one approach, the widths of the lands 1034 of the second block 1030,as measured in the direction orthogonal (into the sheet of FIG. 10) tothe direction of media travel 816, may be less than the width of themedia, but the widths may be wider than the media in other approaches.

As shown, the lands 1034 of the second block 1030 are contoured in orderto reduce interaction of the lands 1034 of the second block 1030 withthe tape media.

The height h₂ of the lands 1034 of the second block 1030 may be at leastas long as the height h₁ of the lands 1004 of the first block 1020.

In one approach, the lands 1034 of the second block 1030 may be alignedto the channels 1006 of the first block 1020 with guide pins (not shown)of conventional type and arrangement.

The second block 1030 may be formed of any desired material. In someapproaches of apparatus 1000, the second block 1030 may includecomposite materials used in tool fabrication, such as silicon, zirconiumnitride, AlTiC, silicon carbide, sapphire, etc.; a ceramic material,such as, calcium titanate; etc.

FIG. 11 depicts an apparatus 1100 for burnishing tape media, inaccordance with one embodiment. As an option, the apparatus 1100 may beimplemented in conjunction with features from any other embodimentlisted herein, such as those described with reference to the other FIGS.Of course, however, such an apparatus 1100 and others presented hereinmay be used in various applications and/or in permutations which may ormay not be specifically described in the illustrative embodiments listedherein. Further, the apparatus 1100 presented herein may be used in anydesired environment.

The apparatus 1100 may have similar features to the apparatus 1000 ofFIG. 10, except as provided below, and accordingly has common numberingwith FIG. 10.

The apparatus 1100 includes lands 1034 of the second block 1030 havingopenings 1022, e.g. cylindrical holes, slots, etc. to allow pressurizedair 1024 to flow against the media to push the media toward the channels1006 of the first block 1020. In some approaches of apparatus 1000, theopenings 1022 may be configured to direct the pressurized air 1024 fromthe openings 1022 to provide an air film between the lands 1034 of thesecond block 1030 and the media for reducing friction between the mediaand the second block.

According to the embodiment shown on FIG. 11, the induced wrap angle maybe set, at least in part, by adjusting the extent of protrusion of thelands 1034 of the second block 1030 into the channels 1006 of the firstblock 1020. The induced wrap angle formed at skiving edges 1008 of thelands 1004 of the first block 1020 as the media travels in the directionof media travel 816 may be greater than zero degrees, and morepreferably in a range of about 0.1 to about 3 degrees.

In some embodiments, the lands 1034 of the second block 1030 arecontoured without sharp edges in order to reduce interaction of thelands 1034 of the second block 1030 with the tape media.

In the embodiment of apparatus 1100, the media bearing surface of eachof the lands 1004 of the first block 1020 may be planar, ideally withsharp, non-cusped edges.

According to one embodiment of a method for using the apparatus 1100,the method may involve running the media over the first block 1020 inthe direction of media travel 816 one or more times.

One embodiment of apparatus 1100 may include a drive mechanism such as amotor or other known mechanism that is configured to cause the tape tomove over the first block and a controller electrically coupled to thedrive mechanism. For example, the motor or other known mechanism maydrive a tape supply cartridge, e.g., tape supply cartridge 120 of FIG.1A, and a take-up reel, e.g., take-up reel 121 also of FIG. 1A, of adrive in which the block is implemented in, to move the tape media overthe block and/or other components of the drive.

In some approaches, the apparatus 1100 may include a mechanism 1050 forremoving accumulated debris from the channels 1006. In one approach, abrush may sweep through the channels 1006 at periodic intervals. Inanother approach, the mechanism may use compressed air. Furtherapproaches may use a fabric, swab or the like to wipe away debris. Infurther approaches, a rotating, vibrating or otherwise moving mechanismmay be used. The mechanism 1050 may be automated, operate on demand,etc.

In another embodiment (not shown, but see FIG. 9 for reference) theapparatus 1100 may include channels of the first block having openingsthat connect to a vacuum source to urge the media toward the mediabearing surface of the lands of the first block. Wrap angles of themedia tape may be adjusted, e.g., to a low or high wrap angle, inresponse to the vacuum urging the magnetic recording tape downward.

In use, the embodiments described herein, of apparatus 800, 900, 1000,and 1100, may be employed in a media formatter, where the servo patternis written to the tape, or before the tape media is used for writing, orafter data has been written to the tape media. Multiple blocks may beused. Moreover, each block may have two or more lands, for example, 4,16, 32, or more pairs of lands and channels. Media may be passed in onlyone or in both directions over the block(s).

It will be clear that the various features of the foregoing systemsand/or methodologies may be combined in any way, creating a plurality ofcombinations from the descriptions presented above.

It will be further appreciated that embodiments of the present inventionmay be provided in the form of a service deployed on behalf of acustomer.

The inventive concepts disclosed herein have been presented by way ofexample to illustrate the myriad features thereof in a plurality ofillustrative scenarios, embodiments, and/or implementations. It shouldbe appreciated that the concepts generally disclosed are to beconsidered as modular, and may be implemented in any combination,permutation, or synthesis thereof. In addition, any modification,alteration, or equivalent of the presently disclosed features,functions, and concepts that would be appreciated by a person havingordinary skill in the art upon reading the instant descriptions shouldalso be considered within the scope of this disclosure.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

What is claimed is:
 1. An apparatus for burnishing media, the apparatuscomprising: a first block with a media bearing surface having aplurality of channels and lands, wherein each of the lands has at leastone skiving edge along a width thereof, the width of each land extendingorthogonally to the direction of media travel; and a mechanism forinducing a wrap angle of the media relative to media bearing surfaces ofat least some of the lands, wherein each induced wrap angle is greaterthan zero degrees, wherein the mechanism includes a second block havinglands facing and extending toward the media bearing surface of the firstblock, the lands of the second block being configured to push the mediainto the channels of the first block.
 2. An apparatus as recited inclaim 1, wherein a width of at least some of the channels is greaterthan a width of the media.
 3. An apparatus as recited in claim 1,wherein the lands of the second block are contoured.
 4. An apparatus asrecited in claim 1, wherein the lands of the second block are aligned tothe channels of the first block.
 5. An apparatus as recited in claim 1,wherein the lands of the second block have openings to allow pressurizedair to flow against the media to push the media toward the channels ofthe first block.
 6. An apparatus as recited in claim 5, wherein theopenings are configured to direct pressurized air from the openings toprovide an air film between the lands of the second block and the mediafor reducing friction between the media and the second block.
 7. Anapparatus as recited in claim 1, wherein each induced wrap angle is in arange of about 0.1 to about 3 degrees.
 8. An apparatus as recited inclaim 1, wherein a media bearing surface of each of the lands is planar.9. An apparatus as recited in claim 1, comprising a mechanism forremoving accumulated debris from the channels.
 10. An apparatus asrecited in claim 1, further comprising: a drive mechanism for passing amagnetic medium over the first block; and a controller electricallycoupled to the drive mechanism.
 11. An apparatus for burnishing media,the apparatus comprising: a first block with a media bearing surfacehaving a plurality of channels and lands, wherein a media bearingsurface of each of the lands is planar, wherein the channels and landsalternate in a direction of media travel, wherein each of the lands hasat least one skiving edge along a width thereof, the width of each landextending orthogonally to the direction of media travel; a mechanism forinducing a wrap angle of the media relative to media bearing surfaces ofat least some of the lands, wherein each induced wrap angle is in arange of about 0.1 to about 3 degrees; and a mechanism for removingaccumulated debris from the channels.
 12. An apparatus as recited inclaim 11, wherein the channels are configured to create a subambient airpressure therein upon movement of the media relative thereto forinducing wrap angles of the media relative to media bearing surfaces ofthe lands, the induced wrap angles being greater than zero degrees. 13.An apparatus as recited in claim 11, wherein the mechanism for inducingthe wrap angles includes a second block positioned above the firstblock, the second block having lands positioned relative to the firstblock to push the media into the channels of the first block.
 14. Anapparatus as recited in claim 13, wherein the lands of the second blockare aligned to the channels of the first block.
 15. An apparatus asrecited in claim 11, wherein the channels of the first block haveopenings that connect to a vacuum source to urge the media toward mediabearing surfaces of the lands of the first block.
 16. An apparatus asrecited in claim 11, further comprising: a drive mechanism for passing amagnetic medium over the first block; and a controller electricallycoupled to the drive mechanism.
 17. A method for burnishing media, themethod comprising: setting a wrap angle of a media relative to a mediabearing surface of an apparatus, wherein the apparatus comprises: afirst block with a media bearing surface having a plurality of channelsand lands, wherein the channels and lands alternate in a direction ofmedia travel, wherein a media facing surface of each of the lands isplanar, wherein each of the lands has at least one skiving edge along awidth thereof, the width of each land extending orthogonally to thedirection of media travel; running the media over the first block in thedirection of media travel; and removing accumulated debris from at leastsome of the channels.
 18. A method for burnishing media as recited inclaim 17, comprising positioning a second block having lands facing andextending toward the media bearing surface of the first block to pushthe media into the channels of the first block.
 19. A method forburnishing media as recited in claim 17, wherein the wrap angle of themedia relative to the media bearing surface of the apparatus is in arange of about 0.1 to about 3 degrees.